Answer:
The given equation H2 + O2 => H2O is not balanced as the oxygen atom on the right side do not have the same number of atoms as of the left side.
In a balanced equation, the number of atoms on both sides are equal. So in this case, we are required to change the coefficient in front of H2O, in order to make oxygen atom balance, for that we need to change the coefficient of H2 as well.
It means to make the given equation balance we need to change the coefficient in front of H2 and H2O.
Balance equation: 2H2 + O2 => 2H2O
